| 摘要 |
An infrared (IR) article or person locator system is described wherein a plurality of stationary units are distributed in zones throughout an enclosure. The article or person carries a portable device so that the infrared communication link can derive local information as to where the article or person is and an RF link is used, instead of cables, to transfer the local information to a central processor or station. In one embodiment local stationary beacons generate location codes at an IR carrier frequency and IR portable devices carry transceivers made of an IR receiver and a portable RF transmitter transmits the location code and a PIN code associated with the portable device to the central station. Techniques are described for reducing electrical power demands on the portable device's battery while enhancing the speed with which the central station can be alerted of a change in the location of the portable device. |
